Magnification viewer

ABSTRACT

A housing for a magnification loupe is provided having a body portion for an eyepiece lens and a nose portion for an objective lens. The body portion for the eyepiece lens includes outer circumferential threads over which the objective nose portion fits. The objective nose portion includes a pin slot defining an arc across the body of the nose. The arc is configured such that a pin may be secured through the holes in the nose piece to co-act with the threads of the eyepiece body such that radial movement is prohibited.

[0001] This application is a divisional of application Ser. No.09/761,086 filed Jan. 15, 2001 (now pending) which is a continuation ofapplication Ser. No. 09/062,936 filed Apr. 20, 1998, now U.S. Pat. No.6,201,640, the disclosure of which is fully incorporated herein byreference.

FIELD OF THE INVENTION

[0002] The present invention relates to magnification viewers worn bysurgeons and dentists. In particular, the invention relates to anassembly for optical views or loupes which allow a user to adjust anobjective lens at a predetermined distance from an eyepiece lens to varythe focal point.

BACKGROUND OF THE INVENTION

[0003] Magnification viewers, including, but not limited to, pairs ofmagnification loupes, are worn by dentists and surgeons for extendedperiods of time during clinical procedures. These viewers are worn toprovide clarity of view while avoiding a hunched-over position that canresult over time in debilitating neck and back strain, which can alsohave an adverse effect on the success of the operation. The viewerspermit the clinician to operate at a greater working distance from thepatient. Higher magnification viewers also reduce the clinician'sexposure to aerosols.

[0004] Because clinicians use magnification viewers during surgery andother procedure requiring manual precision, it is important that theviewers be light-weight, comfortable and have good clarity and widefield of vision while providing high magnification and good depth offield.

[0005] Surgical telescopes may be attached to a spectacle frame in oneof two manners: outside-the-carrier or prescription lens(“outside-the-lens”), on an adjustment mechanism that provides foradjustment of the interpupillary distance and convergent anglevariability, or through-the-lens, permanently cemented and fixed inplace. Magnification viewers used by surgeons and dentists typicallyhave a predetermined magnification. Neither the working distance nor themagnification may be changed without a tedious process of replacingeither individual lens elements or the entire optical loupes themselves.Accordingly, there is a need for a simple method for changing themagnification of viewers being worn by a surgeon or dentist, as well asfor altering the working distance of viewers having a particularmagnification.

SUMMARY OF THE INVENTION

[0006] In accordance with one embodiment of the invention, a housing fora magnification loupe is provided having an eyepiece portion for aneyepiece lens and a nose portion for an objective lens. The body portionfor the eyepiece lens includes outer circumferential threads over whichthe objective nose portion fits. The objective nose portion includes apair of apertures for receiving a pin. The apertures are configured suchthat the pin forms a chord across the body of the nose portion andco-acts with the threads of the eyepiece body forming an axialmechanical stop to prevent the nose portion from being removed duringadjustment.

[0007] Magnification loupes, according to the present invention, includea nose housing for an objective lens and a body housing for an eyepiecelens. The system is configured such that the magnification of themagnification loupe may be changed simply by removing the nose housingand replacing it with another. The working distance for a particularmagnification level may be adjusted by threading or unthreading the nosehousing.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] A better understanding of the present invention is obtained whenthe following detailed description is considered in conjunction with thefollowing drawings in which:

[0009] FIGS. 1A-1C are perspective views of a magnification loupe inaccordance with the present invention illustrating the connection of apair of magnification loupes according to an embodiment of the presentinvention secured through the lenses of a pair of spectacles forming amagnification viewer in accordance with the present invention;

[0010]FIG. 2 is a perspective view of magnification loupes according tothe present invention secured to an adjustable nose piece for securingto a pair of spectacles;

[0011]FIG. 3A is an exploded perspective view of the magnificationloupes assembly for the magnification loupes of FIGS. 1 and 2;

[0012]FIG. 3B is a side cross-sectional view of the magnification loupeof FIG. 3A;

[0013]FIG. 4 is a side-elevation view of a nose housing forming aportion of the magnification viewers of FIGS. 1 and 2;

[0014]FIGS. 5A and 5B are side cross-sectional views and detail sidecross-sectional views, respectively, of the housing of FIG. 4;

[0015]FIG. 6 is a top plan view of the nose housing of FIGS. 4 and 5;

[0016]FIG. 7 is a side elevational view of the eyepiece housing of FIGS.1 and 2;

[0017] FIGS. 8A-8C are side cross-sectional views of the housing of FIG.7, including details thereof;

[0018]FIG. 9 is a top plan view of the eyepiece housing of FIGS. 7 and8;

[0019]FIG. 10 is a side elevational view of a spacer for themagnification loupes of FIGS. 1 and 2;

[0020]FIG. 11 is a side cross-sectional view of the spacer of FIG. 10;

[0021]FIG. 12 is a top elevational view of the spacer of FIGS. 10 and11;

[0022]FIG. 13 is a side elevational view of a field stop of themagnification viewer of FIGS. 1-3;

[0023]FIG. 14 is a side cross-sectional view of the spacer of FIG. 13;

[0024]FIG. 15 is a top plan view of the spacer of FIGS. 13 and 14;

[0025]FIG. 16 is a side elevational view of an objective lens retainerring of the magnification loupes of FIGS. 1-3;

[0026]FIG. 17 is a side cross-sectional view of the objective retainerof FIG. 16;

[0027]FIG. 18 is a top plan view of the objective retainer of FIGS. 16and 17;

[0028]FIGS. 19A and 19B are exploded perspective views of a prismassembly for the magnification loupes of FIGS. 1-3;

[0029]FIGS. 20A, 20B and 21-22 illustrate a prism for the prism assemblyof FIGS. 19A and 19B;

[0030] FIGS. 23-26 illustrate the prims assembly of FIG. 19;

[0031] FIGS. 27-29 illustrate the roof prism of the prism assembly ofFIG. 19;

[0032] FIGS. 30-32 illustrate the second prism of the prism assembly ofFIG. 19;

[0033]FIG. 33 is a diagram of the optical layout of the magnificationloupe of FIG. 31; and

[0034]FIG. 34 is an optical layout diagram of the optical loupe of FIG.31, according to an alternate embodiment.

DETAILED DESCRIPTION

[0035] Turning now to the drawings and with particular attention to FIG.1, a magnification viewer 10 including a pair of spectacles 100 withthrough-the-lens magnification loupes 106 a, 106 b. As illustrated, themagnification loupes 106 a, 106 b are of the Keplerian design. Thespectacles 100 include carrier lenses 102 a, 102 b. The carrier lenses102 a, 102 b may be either piano lenses or prescription lenses. Themagnification loupes 106 a, 106 b are fixed in the carrier lenses 102 a,102 b to provide stereoscopic vision. The magnification loupes 106 a,106 b are set at the user's interpupillary distance converging to adesired working distance, for example, anywhere from 12 to 24 or 13 to21 inches. As will be discussed in greater detail below, from a selectedworking distance, the user has the option to vary the viewing distanceby rotating the objective lens housing or nose housing 108 a, 108 b ofeach magnification loupe 106 a, 106 b to the desired focus. As will bediscussed in more detail below, one of the objective lens housings 108a, 108 b and one of the eyepiece housings 110 a, 110 b are formed withthreads, which cooperate with a pin attached to the other housing toform a threaded coupling. The eyepiece housings, 110 a, 110 b, in turn,are secured to the carrier lenses 102 a, 102 b by various techniques,including a friction fit or with an adhesive, such as epoxy.Alternatively, the eyepiece housings 110 a, 110 b may be secured to thecarrier lenses 102 a, 102 b by way of known threading on the outside ofthe eyepiece housings 110 a, 110 b matching threading on the carrierlenses 102 a, 102 b.

[0036] As will be discussed in greater detail below, magnifications of3.3×, 3.8×, 4.3× and 4.8× are possible, according to one embodiment ofthe invention to provide a wide range of selection. For eachmagnification, working distances of about 12″, 16″ and 24″ may beprovided. The carrier lenses 102 a, 102 b normally enable a user tofocus comfortably at 500 mm, about −2D, a typical reading distance. Themagnification loupes 106 a, 106 b, as will be discussed in greaterdetail below, further include a prism system (FIGS. 19-32). Eachmagnification loupe uses an identical prism and eyepiece lens system.For different magnifications, only the objective lenses are changed. Theuser may create depth of field by adjusting the focal distance of eacheye depending upon the operation being performed. the focuses of each ofthe magnification loupes 106 a, 106 b may be changed independently. Theaperture for the objective lens has been reduced in size to provide anincrease in depth of field at high magnifications while still providingsubstantial light.

[0037] Turning now to FIG. 2, an alternative configuration of themagnification loupes 106 a, 106 b of FIG. 1 is illustrated. It is notedthat for the lens system 20 of FIG. 2, the optical configurations of themagnification loupes 206 a, 206 b are different from thethrough-the-lens configuration of FIG. 1, but the barrels or housingsare similar in that only the objective lens need be changed to providedifferent magnifications. The prism and eyepiece remain the same. Theoptical system 20 of FIG. 2 includes a pair of spectacles 200 includinga pair of carrier lenses 202 a, 202 b and a binocular magnificationviewer 25, including a pair of magnification loupes 206 a, 206 b. Asdiscussed in U.S. Pat. No. 5,667,291, the binocular magnification viewer25 may be attached to the spectacles 200 by a pivot member 250.Alternatively, the magnification loupes 206 a, 206 b, may be mountedclose to the spectacle lenses, for example, about 0.5 mm from thecarrier lenses 202 a, 202 b. The pivot member 250, in turn, is attachedto a bridge 258 which includes a bridge adjustment knob 252 foradjusting a pair of extension of arms 254, 256 to enable theinterpupillary distances of the loupes 206 a, 206 b to be adjusted. Theinterpupillary distance of the magnification loupes 206 a, 206 b mayfurther be adjusted by knobs 260 a, 260 b. The binocular magnificationviewer 25 may be secured to the spectacles 200 by way of a clip, screws,glue or other known methods.

[0038] Mechanical Characteristics

[0039] Turning now to FIG. 3A, an exploded perspective view of themagnification loupes 106 in accordance with the present invention areshown. For the purposes of this discussion, only one of themagnification loupes 106 and its components shall be discussed. It isunderstood, however, that all descriptions are equally applicable toloupe 106 b and its components. The magnification loupes 106 a include anose or objective housing 108 a and a body or eyepiece housing 110 a. Asillustrated, the objective housing 108 a includes a frusto-conical frontportion 350 and a generally cylindrical rear portion 352. It is notedthat the housing 108 a may be of different shapes; thus, FIG. 3 isexemplary only. The objective housing 108 a includes a pair of apertures304. The apertures 304 are configured to receive a pin 302 such that thepin 302 defines a chord across the cylindrical rear portion 352 of theobjective housing 108 a. More particularly with reference to FIG. 3B,the objective housing 108 a includes an interior surface 308 whichengages an exterior surface 307 of the eyepiece housing 110 a. Spiralthreads 306 are formed into the surface of the eyepiece housing 110 a.The apertures 304 are located in the objective housing 108 a so that thepin 302 engage the spirals or threads 306. The pin 302 enables athreaded coupling between the two housings 106 a and 108 a even throughonly one housing 110 a is formed with threads. The threaded couplingbetween the housings 106 a and 108 a permits the working distance of theloupes 106 a and 106 b to be adjusted by rotating the objective housing108 a relative to the eyepiece housing 110 a, which in turn, varies thedistance between the eyepiece and objective lenses which varies theworking distance between the loupes 106 a and 106 b.

[0040] Another important aspect of the invention is that theconfiguration allows the magnification of the loupes 106 a and 106 b tobe rather easily changed. More particularly, the pin 302 may beremovably mounted relative to the objective housing 108 a or fixedlymounted with the use of epoxy. Depending on the embodiment, themagnification of the loupe can be rather easily changed at the factoryor by the user, or both. In particular, as will be discussed in moredetail below, the magnification of the loupe 106 a is changed simply bychanging the objective lens in the loupe 106 a. The objective lenses areeasily changed by removing the pin 302 which enables the objectivehousing 108 a to be removed so that the objective lens 312 can beremoved and replaced. As will be discussed in more detail below, animportant aspect of the invention relates to the ability to vary themagnification of the loupe 106 a.

[0041] As best illustrated in FIGS. 3A and 3B, the objective lens 312 isconfigured to rest within a first interior portion 360 of the objectivehousing 108 a. The interior portion 360 includes a circumferential slot311 for seating an O-ring 310 therein. The objective lens 312 restsagainst the O-ring 310 and is engaged in place by a threaded retainerring 314. The retainer ring 314 includes external threads to engagecorresponding threads on the interior portion 360 of the objectivehousing 1 08 a.

[0042] Additional details concerning the objective housing 108 a areillustrated in FIGS. 4-6. For example, the exterior of the objectivehousing 108 a may include a knurled portion 109 for easy engagement ofthe objective housing 108 a to the eyepiece housing 110 a.

[0043] The eyepiece housing 110 a, illustrated in greater detail inFIGS. 7-9, includes a forward engagement portion 307 and a rearcylindrical portion 309. As discussed above, the forward engagementportion 307 includes threads 306 for engagement with the pin 302. It isnoted that according to one embodiment of the invention, the threads 306are circular threads rather than notched or V-shaped threads so as tomore effectively engage the pin 302. The eyepiece housing 110 a includesinternal threads 340 positioned where the engagement housing 307 meetsthe rear cylindrical portion 309. The threads 340 are configured toengage the threads 341 of the field stop 318 (FIGS. 3A, 3B). The rearcylindrical portion 309 of the eyepiece housing 110 a further includes acircumferential platform 344, configured to receive a lens 332, forexample, a prescription lens. The lens 332 is held in place against theplatform 344 in contact with a prescription lens O-ring 340 and aretainer ring 334, which has external threads that engage the internalthreads 342 of the eyepiece housing 110 a. In the embodimentillustrated, the rear cylindrical portion 309 of the housing 110 a isconfigured to be fastened to the carrier lens 102 a by way of a suitableadhesive, such as epoxy. In an alternative embodiment, however, the rearcylindrical portion 309 may be provided with threads to engage similarthreads in the carrier lens.

[0044] The forward engagement portion 307 of the eyepiece housing 110 ais further configured to receive a prism assembly 316 (FIGS. 19A, 19B).The prism assembly 316 includes a prism holder 317 including a pair ofarms 319 a, 319 b, a base portion 321, and is adapted to fit within thehousing 110 a. The forward portions of the arms 319 a, 319 b includecircular cutout portions 323 a, 323 b, respectively, to engage a holderring 402. The holder ring 402 is configured, when attached in place(such as by an adhesive), to secure the prism elements 404, 406, 408.According to one embodiment, the prism elements (FIGS. 20a-22) form aroof-pechan prism separated by a spacer 408. The spacer 408 is formed,for example, of a blackened ridge metal with a six millimeter diameterhole centered on the optical axis. The prism surfaces on opposite sidesof the spacer are generally parallel. The individual elements of theroof pechan prism 404, 406 are illustrated in FIGS. 23-27 and 28-30,respectively. The prism elements are formed from Schott BAK4 or LAK10glass.

[0045] Turning back to FIGS. 3A-3B, the base of the prism assembly 316is configured to rest against a rear wall 351 of the forward engagementportion 307 at approximately the position where it engages the rearcylindrical portion 309. A field stop 318 (FIGS. 13-15) having externalthreads 341 engages the corresponding internal threads 340 of thehousing 110 a. The field stop 318 further includes internal grooves 343.The rear cylindrical portion 309 of the housing 110 further houses theeyepiece lens elements. As shown, the eyepiece lens includes elements320 and 324, separated by a spacer 322. The spacer 322 is illustrated inFIGS. 10-12 and may include internal concentric grooves 329 which form alight baffle. Finally, the eyepiece lens 324 rests against the platform344.

[0046] The exterior of the engagement housing 307 includes a pair ofconcentric circumferential grooves 325, 327 configured to receive theO-rings 326, 328, respectively. The O-rings 326, 328 additionallyfunction to self-center the objective housing 108 a and hence, theobjective lens 312 relative to the eyepiece housing 110 a.

[0047] While the configuration described and shown with regard to FIGS.3A-3B relates to a through-the-lens viewer, a similar configuration maybe used in the outside-the-lens system shown in FIG. 2. Such a systemmay be used without a prescription lens and, as will be described ingreater detail below, a different eyepiece system.

[0048] Optical Characteristics

[0049] Turning now to FIG. 33, a diagram illustrating the optical layoutof the magnification loupe 106 a of FIGS. 1 and 3A, 3B is shown. Themagnification loupe 106 a as illustrated in FIG. 33 includes atwo-element objective lens including elements I-II and including athree-element eyepiece including elements III-V. R1, R2 etc., representthe radii of respective refractive surfaces; S1-S5 represent thethickness of the air spaces; and T1, T2, etc., represent the thicknessesof the lens elements. As discussed above, according to one embodiment ofthe invention, magnifications of 3.3×, 3.8×, 4.3× and 4.8× are provided.All magnifications use the same prism and eyepiece lens system. As shownin FIGS. 28 and 32, the prior angle ∝ may be used in the range 45°-49°,preferably 48° to increase the optical performance of the device whilethe prism angle B (FIG. 32) may be selected to be 24°. Thus, a commoneyepiece housing 110 a and optical elements included therein may be usedfor all of the magnifications. As discussed above, only the objectivelens needs to be changed in order to alter the magnification.

[0050] The user may create a depth of field by adjusting the focaldistance of each eye differently depending on the operation beingperformed. For example, a heart surgeon may wish to view the entiredepth of the heart at high magnification previously unattainable inconventional magnification systems where depth of field is limited. Thiscan be accomplished by adjusting the focus of the left eye one-inchbeyond the right. When both eyes are then opened, the heart can beviewed in its entirety. However, a dentist may only require the depth ofthe coronal portion of the tooth to be in focus and thus would onlyseparate the focus by a millimeter or two. Alternatively, bothmagnification loupes can be precisely focused at the same distance forprocedures requiring the highest resolution. The following exemplaryfields of view may be provided:

[0051] 93 m @ 3.3×@ 16″ WD

[0052] 82 m @ 3.8×@ 16″ WD

[0053] 72 m @ 4.3×@ 16″ WD

[0054] 65 m @ 4.8×@ 16″WD

[0055] Exemplary construction data for a magnification loupe builtaccording to the embodiment shown in FIGS. 1-3 are given in TablesI-XII. The radii, thickness, and separation dimensions are given inmillimeters. Roman numerals identify the lens elements in theirrespective order from the objective side to the eyepoint side; n_(d)represents the refractive index of each element; v_(d) is the abbedispersion number; R1, R1, etc., represent the radii of the respectiverefractive surfaces in order from the objective side to the eyepointside; T1, T2, etc., represent the thicknesses of the lens elements fromthe objective side to the eyepoint side; S1, S2, etc., represent thethicknesses of air spaces respectively from the objective side to theeyepoint side measured along the optical centerline. Again, it is notedthat the prism/objective distance can differ by about 2.5 mm if BAK4glass is used, rather than LAK10, as in the tables.

[0056]FIG. 34 illustrates an embodiment of the present invention havinglong eye relief characteristics. Again, the system shown in FIG. 34employs the same prism and eyepieces, but separate objective doubletsfor each level of magnification. The objective doublets and the prism,however, are the same as for the through-the-lens embodiment shown inFIG. 33. Additionally, only the eyepiece lens is changed from thethrough-the-lens configuration. As compared the embodiment of FIG. 33eye relief (the distance to exit pupil) has been improved from about17.8 mm to about 22.8 mm.

[0057] In particular, the viewer according to FIG. 34 includes thetwo-element or doublet objective including elements I-II and afour-element eyepiece lens including elements III-VI. R1, R2, etc.,again represent the radii of respective refractive surfaces; S1, S2,etc., represent the thicknesses of the air spaces; and T1, T2, etc.,represent the thicknesses of the lens elements.

[0058] Exemplary construction data for loupes according to theembodiment of FIG. 34 are given in Tables XIII-XXIV. TABLE I 3.3X (12″WD) Di- Ele- Thick- am- ment Glass nd vd Radius ness eter Sep. I Ohara1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45 II Ohara 1.8052 25.4R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism BAK4 1.5688 56.13 S₁ = 6.96 ALAK10 1.7200 50.41 S₂ = 3.41 S₃ = 7.04 Prism BAK4 1.5688 56.13 S₄ = 0.05B LAK10 1.7200 50.41 S₅ = 17.86 III Ohara 1.8052 25.4 R₃ = 44.00 2.015.4 PBH6W R₄ = 13.00 IV Ohara 1.4875 70.2 R₅ = 13.00 6.5 15.4 FSL5 R₆ =13.00 V Ohara 1.6700 47.3 R₇ = 15.59 3.0 15.4 BAH10 R₈ = 94.04

[0059] TABLE II 3.3X (16″ WD) Di- Ele- Thick- am- ment Glass nd vdRadius ness eter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂= 12.45 II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 PrismBAK4 1.5688 56.13 S₁ = 5.01 A LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 7.04Prism BAK4 1.5688 56.13 S₄ = 0.05 B LAK10 1.7200 50.41 S₅ = 17.86 IIIOhara 1.8052 25.4 R₃ = 44.00 2.0 15.4 PBH6W R₄ = 13.00 IV Ohara 1.487570.2 R₅ = 13.00 6.5 15.4 FSL5 R₆ = 13.00 V Ohara 1.6700 47.3 R₇ = 15.593.0 15.4 BAH10 R₈ = 94.04

[0060] TABLE III 3.3X (24″ WD) Di- Ele- Thick- am- ment Glass nd vdRadius ness eter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂= 12.45 II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 PrismBAK4 1.5688 56.13 S₁ = 3.63 A LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 7.04Prism BAK4 1.5688 56.13 S₄ = 0.05 B LAK10 1.7200 50.41 S₅ = 17.86 IIIOhara 1.8052 25.4 R₃ = 44.00 2.0 15.4 PBH6W R₄ = 13.00 IV Ohara 1.487570.2 R₅ = 13.00 6.5 15.4 FSL5 R₆= 13.00 V Ohara 1.6700 47.3 R₇ = 15.593.0 15.4 BAH10 R₈ = 94.04

[0061] TABLE IV 3.8X (12″ WD) Di- Ele- Thick- am- ment Glass nd vdRadius ness eter Sep. I Ohara 1.7015 41.2 R₁ = 42.04 4.0 13.4 BAH 27 R₂= 14.61 II Ohara 1.8052 25.4 R₂ = 14.61 1.5 13.4 PBH6W R₃ = 36.00 PrismBAK4 1.5688 56.13 S₁ = 12.38 A LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 7.04Prism BAK4 1.5688 56.13 S₄ = 0.05 B LAK10 1.7200 50.41 S₅ = 17.86 IIIOhara 1.8052 25.4 R₃ = 44.00 2.0 15.4 PBH6W R₄ = 13.00 IV Ohara 1.487570.2 R₅ = 13.00 6.5 15.4 FSL5 R₆ = 13.00 V Ohara 1.6700 47.3 R₇ = 15.593.0 15.4 BAH10 R₈ = 94.04

[0062] TABLE V 3.8X (16″ WD) Di- Ele- Thick- am- ment Glass nd vd Radiusness eter Sep. I Ohara 1.7015 41.2 R₁ = 42.04 4.0 13.4 BAH 27 R₂ = 14.61II Ohara 1.8052 25.4 R₂ = 14.61 1.5 13.4 PBH6W R₃ = 36.00 Prism BAK41.5688 56.13 S₁ = 9.92 A LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 7.04 PrismBAK4 1.5688 56.13 S₄ = 0.05 B LAK10 1.7200 50.41 S₅ = 17.86 III Ohara1.8052 25.4 R₃ = 44.00 2.0 15.4 PBH6W R₄ = 13.00 IV Ohara 1.4875 70.2 R₅= 13.00 6.5 15.4 FSL5 R₆ = 13.00 V Ohara 1.6700 47.3 R₇ = 15.59 3.0 15.4BAH10 R₈ = 94.04

[0063] TABLE VI 3.8X (24″ WD) Di- Ele- Thick- am- ment Glass nd vdRadius ness eter Sep. I Ohara 1.7015 41.2 R₁ = 42.04 4.0 13.4 BAH 27 R₂= 14.61 II Ohara 1.8052 25.4 R₂ = 14.61 1.5 13.4 PBH6W R₃ = 36.00 PrismBAK4 1.5688 56.13 S₁ = 8.02 A LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 7.04Prism BAK4 1.5688 56.13 S₄ = 0.05 B LAK10 1.7200 50.41 S₅ = 17.86 IIIOhara 1.8052 25.4 R₃ = 44.00 2.0 15.4 PBH6W R₄ = 13.00 IV Ohara 1.487570.2 R₅ = 13.00 6.5 15.4 FSL5 R₆ = 13.00 V Ohara 1.6700 47.3 R₇ = 15.593.0 15.4 BAH10 R₈ = 94.04

[0064] TABLE VII 4.3X (12″ WD) Di- Ele- Thick- am- ment Glass nd vdRadius ness eter Sep. I Ohara 1.7015 41.2 R₁ = 50.15 4.0 13.4 BAH 27 R₂= 16.00 II Ohara 1.8052 25.4 R₂ = 16.00 1.5 13.4 PBH6W R₃ = 47.79 PrismBAK4 1.5688 56.13 S₁ = 18.07 A LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 7.04Prism BAK4 1.5688 56.13 S₄ = 0.05 B LAK10 1.7200 50.41 S₅ = 17.86 IIIOhara 1.8052 25.4 R₃ = 44.00 2.0 15.4 PBH6W R₄ = 13.00 IV Ohara 1.487570.2 R₅ = 13.00 6.5 15.4 FSL5 R₆ = 13.00 V Ohara 1.6700 47.3 R₇ = 15.593.0 15.4 BAH10 R₈ = 94.04

[0065] TABLE VIII 4.3X (16″ WD) Di- Ele- Thick- am- ment Glass nd vdRadius ness eter Sep. I Ohara 1.7015 41.2 R₁ = 50.15 4.0 13.4 BAH 27 R₂= 16.00 II Ohara 1.8052 25.4 R₂ = 16.00 1.5 13.4 PBH6W R₃ = 47.79 PrismBAK4 1.5688 56.13 S₁ = 15.56 A LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 7.04Prism BAK4 1.5688 56.13 S₄ = 0.05 B LAK10 1.7200 50.41 S₅ = 17.86 IIIOhara 1.8052 25.4 R₃ = 44.00 2.0 15.4 PBH6W R₄ = 13.00 IV Ohara 1.487570.2 R₅ = 13.00 6.5 15.4 FSL5 R₆ = 13.00 V Ohara 1.6700 47.3 R₇ = 15.593.0 15.4 BAH10 R₈ = 94.04

[0066] TABLE IX 4.3X (24″ WD) Di- Ele- Thick- am- ment Glass nd vdRadius ness eter Sep. I Ohara 1.7015 41.2 R₁ = 50.15 4.0 13.4 BAH 27 R₂= 16.00 II Ohara 1.8052 25.4 R₂ = 16.00 1.5 13.4 PBH6W R₃ = 47.79 PrismBAK4 1.5688 56.13 S₁ = 13.13 A LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 7.04Prism BAK4 1.5688 56.13 S₄ = 0.05 B LAK10 1.7200 50.41 S₅ = 17.86 IIIOhara 1.8052 25.4 R₃ = 44.00 2.0 15.4 PBH6W R₄ = 13.00 IV Ohara 1.487570.2 R₅ = 13.00 6.5 15.4 FSL5 R₆ = 13.00 V Ohara 1.6700 47.3 R₇ = 15.593.0 15.4 BAH10 R₈ = 94.04

[0067] TABLE X 4.8X (12″ WD) Di- Ele- Thick- am- ment Glass nd vd Radiusness eter Sep. I Ohara 1.7015 41.2 61.12 4.0 13.4 BAH 27 II Ohara 1.805225.4 16.98 1.5 13.4 SFL6 Prism BAK4 1.5688 56.13 S₁ = 25.16 A LAK101.7200 50.41 S₂ = 3.41 S₃ = 7.04 Prism BAK4 1.5688 56.13 S₄ = 0.05 BLAK10 1.7200 50.41 S₅ = 17.86 III Ohara 1.8052 25.4 R₃ = 44.00 2.0 15.4PBH6W R₄ = 13.00 IV Ohara 1.4875 70.2 R₅ = 13.00 6.5 15.4 FSL5 R₆ =13.00 V Ohara 1.6700 47.3 R₇ = 15.59 3.0 15.4 BAH10 R₈ = 94.04

[0068] TABLE XI 4.8X (16″ WD) Element Glass nd vd Radius ThicknessDiameter Sep. I Ohara 1.7015 41.2 61.12 4.0 13.4 BAH 27 II Ohara 1.805225.4 16.98 1.5 13.4 SFL6 Prism A BAK4 1.5688 56.13 S₁ = 21.23 LAK101.7200 50.41 S₂ = 3.41 S₃ = 7.04 Prism B BAK4 1.5688 56.13 S₄ = 0.05LAK10 1.7200 50.41 S₅ = 17.86 III Ohara 1.8052 25.4 R₃ = 44.00 2.0 15.4PBH6W R₄ = 13.00 IV Ohara 1.4875 70.2 R₅ = 13.00 6.5 15.4 FSL5 R₆ =13.00 V Ohara 1.6700 47.3 R₇ = 15.59 3.0 15.4 BAH10 R₈ = 94.04

[0069] TABLE XII 4.8X (24″ WD) Element Glass nd vd Radius ThicknessDiameter Sep. I Ohara 1.7015 41.2 61.12 4.0 13.4 BAH 27 II Ohara 1.805225.4 16.98 1.5 13.4 SFL6 Prism A BAK4 1.5688 56.13 S₁ = 18.22 LAK101.7200 50.41 S₂ = 3.41 S₃ = 7.04 Prism B BAK4 1.5688 56.13 S₄ = 0.05LAK10 1.7200 50.41 S₅ = 17.86 III Ohara 1.8052 25.4 R₃ = 44.00 2.0 15.4PBH6W R₄ = 13.00 IV Ohara 1.4875 70.2 R₅ = 13.00 6.5 15.4 FSL5 R₆ =13.00 V Ohara 1.6700 47.3 R₇ = 15.59 3.0 15.4 BAH10 R₈ = 94.04

[0070] TABLE XIII 3.3X (12″ WD) Thick- Element Glass nd vd Radius nessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 6.96 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0071] TABLE XIV 3.3X (16″ WD) Thick- Element Glass nd vd Radius nessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 5.1 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0072] TABLE XV 3.3X (24″ WD) Thick- Element Glass nd vd Radius nessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 3.63 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0073] TABLE XVI 3.8X (12″ WD) Thick- Element Glass nd vd Radius nessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 12.38 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0074] TABLE XVII 3.8X (16″ WD) Thick- Element Glass nd vd Radius nessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 9.92 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0075] TABLE XVIII 3.8X (24″ WD) Thick- Element Glass nd vd Radius nessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 8.02 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0076] TABLE XIX 4.3X (12″ WD) Thick- Element Glass nd vd Radius nessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 18.7 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0077] TABLE XVIII 4.3X (16″ WD) Thick- Element Glass nd vd Radius nessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 15.56 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0078] TABLE XXI 4.3X (24″ WD) Element Glass nd vd Radius ThicknessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 13.13 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0079] TABLE XXII 4.8X (12″ WD) Element Glass nd vd Radius ThicknessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 25.16 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0080] TABLE XXIII 4.8X (16″ WD) Element Glass nd vd Radius ThicknessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 21.23 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0081] TABLE XXIV 4.8X (24″ WD) Element Glass nd vd Radius ThicknessDiameter Sep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45II Ohara 1.8052 25.4 R₂ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK41.5688 56.13 S₁ = 18.22 LAK10 1.7200 50.41 S₂ = 3.41 S₃ = 2.33 Prism BBAK4 1.5688 56.13 S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.541047.2 R₄ = PLANO 3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ =12.61 1.5 15.4 PBH71 R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4BK7 R₆ = 12.61 VI SCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ =25.11

[0082] The invention described in the above detailed description is notintended to be limited to the specific form set forth herein, but, onthe contrary, is intended to cover such alternative, modifications andequivalents as can reasonably be included within the spirit and scope ofthe appended claims.

We claim:
 1. A magnification loupe carried by spectacles, comprising: atwo-element eyepiece lens; a three-element objective lens; and atwo-element prism disposed between said eyepiece lens and said objectivelens; the loupe having a working distance in the range of approximately12 inches to approximately 24 inches; the loupe having a magnificationin the range of approximately 3.3 to approximately 4.8; the spacing S₁between said eyepiece lens and said prism, along an optical centerline,in the range of approximately 3.63 mm to approximately 25.16 mm; whereinthe said lenses and said prism are constructed and arranged according tothe following parameters: Element Glass nd vd Radius Thickness DiameterSep. I Ohara 1.7015 41.2 R₁ = 42.19 3.5 13.4 BAH 27 R₂ = 12.45 II Ohara1.8052 25.4 R₃ = 12.45 1.5 13.4 PBH6W R₃ = 36.00 Prism A BAK4 1.568856.13 S₂ = 3.41 LAK10 1.7200 50.41 S₃ = 2.33 Prism B BAK4 1.5688 56.13S₄ = 0.5 LAK10 1.7200 50.41 S₅ = 22.8 III Ohara 1.5410 47.2 R₄ = PLANO3.0 12.0 S-TIL2 R₅ = 12.61 IV Ohara 1.923 21.3 R₅ = 12.61 1.5 15.4 PBH71R₆ = 12.61 V SCHOTT 1.5168 64.2 R₇ = 10.06 7.1 15.4 BK7 R₆ = 12.61 VISCHOTT 1.744 44.8 R₈ = 25.11 4.7 17.5 S-LAM2 R₉ = 25.11

wherein the Roman numerals I-VI identify respective lens elements ofsaid eyepiece lens and said objective lens, from eyepoint side to objectside; nd represents the refractive index of each element; vd is the Abbedispersion number; R1-R9 represent the radii, in millimeters, of therespective refractive surfaces, in order from the eyepiece side to theobject side; and the thickness and separation parameters represent thethicknesses of the lens elements and the air spaces, respectively, inmillimeters, from the eyepoint side to the object side, measured alongan optical centerline.
 2. The magnification loupe of claim 1, whereinthe loupe has a working distance of 12 inches, a magnification of 3.3and said spacing between said eyepiece and said prism is 6.96 mm.
 3. Themagnification loupe of claim 1, wherein the loupe has a working distanceof 16 inches, a magnification of 3.3 and said spacing between saideyepiece lens and said prism is 5.1 mm.
 4. The magnification loupe ofclaim 1, wherein the loupe has a working distance of 24 inches, amagnification of 3.3 and said spacing between said eyepiece lens andsaid prism is 3.63 mm.
 5. The magnification loupe of claim 1, whereinthe loupe has a working distance of 12 inches, a magnification of 3.8and said spacing between said eyepiece lens and said prism is 12.38 mm.6. The magnification loupe of claim 1, wherein the loupe has a workingdistance of 16 inches, a magnification of 3.8 and said spacing betweensaid eyepiece lens and said prism is 9.92 mm.
 7. The magnification loupeof claim 1, wherein the loupe has a working distance of 24 inches, amagnification of 3.8 and said spacing between said eyepiece lens andsaid prism is 8.02 mm.
 8. The magnification loupe of claim 1, whereinthe loupe has a working distance of 12 inches, a magnification of 4.3and said spacing between said eyepiece lens and said prism is 18.7 mm.9. The magnification loupe of claim 1, wherein the loupe has a workingdistance of 16 inches, a magnification of 4.3 and said spacing betweensaid eyepiece lens and said prism is 15.56 mm.
 10. The magnificationloupe of claim 1, wherein the loupe has a working distance of 24 inches,a magnification of 4.3 and said spacing between said eyepiece lens andsaid prism is 13.13 mm.
 11. The magnification loupe of claim 1, whereinthe loupe has a working distance of 12 inches, a magnification of 4.8and said spacing between said eyepiece lens and said prism is 25.16 mm.12. The magnification loupe of claim 1, wherein the loupe has a workingdistance of 16 inches, a magnification of 4.8 and said spacing betweensaid eyepiece lens and said prism is 21.23 mm.
 13. The magnificationloupe of claim 1, wherein the loupe has a working distance of 24 inches,a magnification of 4.8 and said spacing between said eyepiece lens andsaid prism is 18.22 mm.